(a) Field of the Invention
The present invention relates to a thin film transistor (TFT) array substrate for liquid crystal displays and a method for fabricating the same and, more particularly, to a TFT array substrate of good performance characteristics.
(b) Description of the Related Art
Generally, a liquid crystal display (LCD) is formed with two glass substrates, and a liquid crystal sandwiched in-between the substrates.
One of the substrates has a common electrode, a color filter and a black matrix, and the other substrate has pixel electrodes and thin film transistors (TFTs). The former substrate is usally called the “color filter substrate,” and the latter substrate called the “TFT array substrate.”
The TFT array substrate is fabricated through forming a plurality of thin films, and performing photolithography with respect to the thin films. In photolithograpy, a number of masks are used for uniformly etching the thin films, involving complicated processing steps and increased production cost. Therefore, reduction in the number of masks becomes a critical factor in the fabrication of the TFT array substrate.
On the other hand, the color filter substrate is provided with a black matrix. The black matrix should be formed with a predetermined degree of marginal width considering the possible alignment error when assembling the color filter substrate and the TFT array substrate. However, the wider black matrix reduces the opening ratio. Therefore, it is required to increase the opening ratio of the black matrix while maintaining other performance characteristics in a stable manner.